Wireless communication system

ABSTRACT

Methods and apparatus for communicating circuit switched voice data with a first cellular radio access network (RAN) and communicating voice over Internet protocol (VoIP) packets using session initiation protocol (SIP) with a second cellular RAN. The second cellular RAN does not support circuit switched voice communication.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/606,661, filed May 26, 2017, which is a continuation of U.S. patentapplication Ser. No. 15/141,932, filed Apr. 29, 2016, which issued onMay 30, 2017 as U.S. Pat. No. 9,667,438, which is a continuation of U.S.patent application Ser. No. 14/551,381, filed Nov. 24, 2014, whichissued on May 31, 2016 as U.S. Pat. No. 9,357,390, which is acontinuation of U.S. patent application Ser. No. 13/872,792, filed Apr.29, 2013, which issued on Nov. 25, 2014 as U.S. Pat. No. 8,897,186,which is a continuation of U.S. patent application Ser. No. 10/329,033,filed Dec. 23, 2002, which issued on Apr. 30, 2013 as U.S. Pat. No.8,432,893 B2, which claims the benefit of U.S. Provisional ApplicationNo. 60/367,949, filed Mar. 26, 2002; U.S. Provisional Application No.60/367,975, filed Mar. 26, 2002; U.S. Provisional Application No.60/367,946, filed Mar. 26, 2002; U.S. Provisional Application No.60/367,945, filed Mar. 26, 2002; U.S. Provisional Application No.60/367,950, filed Mar. 26, 2002; and U.S. Provisional Application No.60/367,948, filed Mar. 26, 2002, which are incorporated by reference asif fully set forth.

FIELD OF INVENTION

The present invention relates to wireless telecommunications including aRadio Access Network (RAN) gateway, and connection and communication ofthe gateway with the Internet.

BACKGROUND

Wireless telecommunication systems are well known in the art. Wirelesssystems require an available bandwidth in which to operate. Typically,the permission to use a portion of the available spectrum for wirelesscommunication for a particular geographic region is obtained from anappropriate governmental unit of the physical territory in which thewireless communications are to be conducted. In order to make efficientuse of limited spectrum available for operation of a wirelesstelecommunication system, Code Division Multiple Access (CDMA) systemshave been developed which include Time Division Duplex (TDD) modes whichprovide a very flexible framework for providing concurrent wirelesscommunication services. Supported wireless communication services can beany of a variety of types including voice, fax, and a host of other datacommunication services.

In order to provide global connectivity for CDMA systems, standards havebeen developed and are being implemented. One current standard inwidespread use is known as Global System for Mobile Telecommunications(GSM). This was followed by the so-called Second Generation mobile radiosystem standards (2G) and its revision (2.5G). Each one of thesestandards sought to improve upon the prior standard with additionalfeatures and enhancements. In January 1998, the EuropeanTelecommunications Standard Institute—Special Mobile Group (ETSI SMG)agreed on a radio access scheme for Third Generation Radio Systemscalled Universal Mobile Telecommunications Systems (UMTS). To furtherimplement the UMTS standard, the Third Generation Partnership Project(3GPP) was formed in December 1998. 3GPP continues to work on a commonthird generational mobile radio standard.

A typical UMTS system architecture in accordance with current 3GPPspecifications is depicted in FIGS. 1 and 2. The UMTS networkarchitecture includes a Core Network (CN) interconnected with a UMTSTerrestrial Radio Access Network (UTRAN) via an interface known as IUwhich is defined in detail in the current publicly available 3GPPspecification documents.

The UTRAN is configured to provide wireless telecommunication servicesto users through User Equipments (UEs) via a radio interface known asUU. The UTRAN has base stations, known as Node Bs in 3GPP, whichcollectively provide for the geographic coverage for wirelesscommunications with UEs. In the UTRAN, groups of one or more Node Bs areconnected to a Radio Network Controller (RNC) via an interface known asIub in 3GPP. The UTRAN may have several groups of Node Bs connected todifferent RNCs, two are shown in the example depicted in FIG. 1. Wheremore than one RNC is provided in a UTRAN, inter-RNC communication isperformed via an Iur interface.

A UE will generally have a Home UMTS Network (HN) with which it isregistered and through which billing and other functions are processed.By standardizing the Uu interface, UEs are able to communicate viadifferent UMTS networks that, for example, serve different geographicareas. In such case the other network is generally referred to as aForeign Network (FN).

Under current 3GPP specifications, the Core Network of a UE's HN servesto coordinate and process the functions of Authentication, Authorizationand Accounting (AAA functions). When a UE travels beyond its Home UMTSNetwork, the HN's Core Network facilitates the UE's use of a ForeignNetwork by being able to coordinate the AAA functions so that the FNwill permit the UE to conduct communications. To assist in implementingthis activity, the Core Network includes a Home Location Register (HLR)which tracks the UEs for which it is the HN and a Visitor LocationRegister (VLR). A Home Service Server (HSS) is provided in conjunctionwith the HLR to process the AAA functions.

Under current 3GPP specifications, the Core Network, but not the UTRAN,is configured with connectivity to external systems such as Public LandMobile Networks (PLMN), Public Switch Telephone Networks (PSTN),Integrated Services Digital Network (ISDN) and other Real Time (RT)services via an RT service interface. A Core Network will also supportNon-Real Time services with the Internet. External connectivity of theCore Network to other systems, enables users using UEs to communicatevia their Home UMTS Network, beyond the area served by the HN's UTRAN.Visiting UEs can likewise communicate via a visited UMTS Network, beyondthe area served by the visited UMTS's UTRAN.

Under current 3GPP specifications, the Core Network provides RT serviceexternal connectivity via a Gateway Mobile Switching Center (GMSC). TheCore Network provides NRT service, known as General Packet Radio Service(GPRS), external connectivity via a Gateway GPRS Support Node (GGSN). Inthis context, a particular NRT service may actually appear to a user tobe a real time communication due to the communication speed andassociated buffering of the TDD data packets forming the communication.One example of this is voice communication via the Internet which canappear to the user as a normal telephone call conducted by a switchingnetwork, but is actually being conducted using an Internet Protocol (IP)connection which provides Packet data Service.

A standard interface known as GI is generally used between a CN's GGSNand the Internet. The GI interface can be used with Mobile InternetProtocols, such as Mobile IP v4 or Mobile IP v6 as specified by theInternet Engineering Task Force (IETF).

Under current 3GPP specifications, to provide support for both RT andNRT services from external sources for radio linked UEs in a 3GPPsystem, the UTRAN must properly interface with the CN which is thefunction of the Iu interface. To do this, the Core Network includes aMobile Switching Centre (MSC) that is coupled to the GMSC and a ServingGPRS Support Node (SGSN) that is coupled to the GGSN. Both are coupledwith the HRL and the MSC is usually combined with the Visitor LocationRegister (VLR).

The Iu interface is divided between an interface for Circuit Switchedcommunications (Iu-CS) and an interface for packet data via PacketSwitched communications (Iu-PS). The MSC is connected to the RNCs of theUTRAN via the Iu-CS interface. The Serving GPRS Support Node (SGSN) iscoupled to the UTRAN's RNCs via the Iu-PS interface for Packet DataServices.

The HLR/HSS is typically interfaced with the CS side of the CoreNetwork, MSC and GMSC via an interface known as Gr which supports AAAfunctions through a Mobile Application Part (MAP) Protocol. The SGSN andthe GGSN of the CN are connected using interfaces known as Gn and Gp.

Common to 3GPP systems and other systems which utilize TDD-CDMAtelecommunications, such as some GSM systems, is the aforementioneddivision of connectivity between the radio network and the Core Network.In general, the radio network, i.e. the UTRAN in 3GPP, communicates viaa wireless interface with UEs and the Core Network communicates withexternal systems via RT and NRT service connections. Applicants haverecognized this standardized type of architecture is most likely theresult of the processing of the AAA functions in the Core Network.However, applicants have further recognized that even if the AAAfunctions are to be maintained in the Core Network, significantadvantages and benefits can be obtained by providing direct connectivityfrom a TDD-CDMA radio network to the Internet.

In particular, Applicants have recognized that the existing separationof functions of the Iu interface defined in 3GPP for Circuit Switched(CS) communications used with Real Time services (Iu-CS interface) anddefined in 3GPP for Packet Switch (PS) service used with Non-Real Timeservices (Iu-PS interface), enables one to easily provide an IP Gatewayin the UTRAN for enabling the UTRAN to direct connectivity to theInternet bypassing use of a Core Network for this function. Moreover, asa result, Applicants have recognized that by permitting direct access tothe Internet from the UTRAN, a Radio Local Area Network is defined thatcan provide significant benefits and advantages for use with or withouta Core Network.

Further detail of a typical 3GPP system is illustrated in FIG. 3. TheUTRAN segment of a conventional UMTS architecture is split it into twotraffic planes known as the C- and U-planes. The C-plane carries control(signaling) traffic, and the U-plane transports user data. Theover-the-air segment of the UTRAN involves two interfaces: the Uuinterface between UE and Node B, and the Iub interface between the NodeB and RNC. As noted above, the back-end interface between the RNC andcore network is referred to as the Iu interface, split into the Iu-CSfor the circuit-switched connection into the MSC, and the Iu-PS for thepacket-switched connection into the SGSN.

The most significant signaling protocol on the over-the-air segment ofthe UTRAN is Radio Resource Control (RRC). RRC manages the allocation ofconnections, radio bearers and physical resources over the airinterface. In 3GPP, RRC signaling is carried over the Radio Link Control(RLC) and Medium Access Control (MAC) UMTS protocols between the UE andRNC. Overall, the RNC is responsible for the allocation/de-allocation ofradio resources, and for the management of key procedures such asconnection management, paging and handover. Over the Iub interface,RRC/RLC/MAC messaging is typically carried on a Transport Layer viaAsynchronous Transfer Mode (ATM), using the ATM Adaptation Layer Type 5(AAL5) protocol over the ATM physical layer with intermediary protocols,such as Service Specific Co-ordination Function (SSCF) and the ServiceSpecific Connection Oriented Protocol SSCOP, being used above AAL5.

U-plane data (e.g. speech, packet data, circuit-switched data) uses theRLC/MAC layers for reliable transfer over the air interface (between UEand RNC). Over the Iub segment, this data flow (user data/RLC/MAC)occurs over UMTS-specified frame protocols using the ATM AdaptationLayer Type 2 (AAL2) protocol over the ATM physical layer running(AAL2/ATM).

The Iu interface carries the Radio Access Network Application Part(RANAP) protocol. RANAP triggers various radio resource management andmobility procedures to occur over the UTRAN, and is also responsible formanaging the establishment/release of terrestrial bearer connectionsbetween the RNC and SGSN/MSC. RANAP is carried over AAL5/ATM, withintermediary Signaling System 7 (SS7) protocols, such as SignalingConnection Control Part, Message Transfer Part (SCCP/MTP) on top of SSCFand the Service Specific Connection Oriented Protocol (SSCOP), beingused above AAL5. Internet Protocol is typically used over AAL5/ATM forthe Iu-PS interface so that the intermediate Stream Control TransmissionProtocol (SCTP) is then used over IP. Where multiple RNCs exist in aUTRAN which have an Iur interface, IP is also commonly used over ATM andintermediate protocols include SSCP, SCTP and the Message Transfer Partlevel 3 SCCP adaptation layer of SS7 (M3UA) that have been developed byIETF.

For the U-Plane, between the UTRAN and the CN, circuit-switchedvoice/data traffic typically flows over AAL5/ATM, via the Iu-CSinterface, between the RNC and MSC. Packet-switched data is carried overthe Iu-PS interface between the RNC and SGSN, using the GPRS TunnelingProtocol (GTP) running over the User Data Protocol for the InternetProtocol (UDP/IP) over AAL5/ATM.

Applicants have recognized that this architecture can be improved uponin connection with providing direct IP connectivity for the UTRAN.

SUMMARY

The present invention provides for a Time Division Duplex—Radio LocalArea Network (TDD-RLAN) which includes a Radio Access Network InternetProtocol (RAN IP) gateway that enables connectivity to the publicInternet. The system may serve as a stand-alone system or beincorporated into a UMTS used with conventional Core Network,particularly for tracking and implementing AAA functions in the CoreNetwork.

The RLAN provides concurrent wireless telecommunication services for aplurality of user equipments (UEs) between UEs and/or the Internet. TheRLAN includes at least one base station that has a transceiver forconducting time division duplex (TDD) code division multiple access(CDMA) wireless communications with UEs in a selected geographic region.The RLAN also has at least one controller that is coupled with a groupof base stations, which includes the base station. The controllercontrols the communications of the group of base stations. A novel RadioAccess Network Internet Protocol (RAN IP) Gateway (RIP GW) is coupledwith the controller. The RAN IP Gateway has a Gateway General PacketRadio Service (GPRS) Support Node (GGSN) with access router functionsfor connection with the Internet.

The RLAN can include a plurality of base stations, each having atransceiver configured with a Uu interface for conducting time divisionduplex (TDD) wideband code division multiple access (W-CDMA) wirelesscommunications with UEs in a selected geographic region. The RLAN canalso include a plurality of controllers that are each coupled with agroup of base stations.

Preferably, the RAN IP Gateway has a Serving GPRS Support Node (SGSN)that is coupled with one or more controllers in the RLAN. Preferably,the controllers are Radio Network Controller (RNCs) in accordance with3GPP specification. Preferably, the RNCs are coupled with the basestations using a stacked, layered protocol connection having a lowertransport layer configured to use Internet Protocol (IP). Where the RLANhas multiple RNCs, the RNCs are preferably coupled to each other using astacked, layered protocol connection having a lower transport layerconfigured to use Internet Protocol (IP)

Methods of mobility management using a radio local area network (RLAN)are disclosed for providing concurrent wireless telecommunicationservices for a plurality of UEs where an associated core network (CN)supports Authentication, Authorization and Accounting (AAA) functions ofUEs. A RLAN conducts TDD-CDMA wireless communications with UEs in a RLANservice region. The RLAN has a RAN IP Gateway that has a GPRS connectionwith the Internet and is configured to communicate AAA functioninformation to the associated CN.

In one method, a wireless connection is established between a first UEwithin the RLAN service region and a second UE outside of the RLANservice region for conducting a communication of user data. AAAfunctions for said communication between said first and second UEs areconducted using the Core Network. The GPRS connection with the Internetis used for transporting user data of the communication between thefirst and second UEs. The method may include continuing the wirelesscommunication between the first and second UEs as the second UE movesfrom outside to within the RLAN service region, where use of the GPRSconnection with the Internet for transporting user data is discontinued.The method can further include continuing the wireless communicationbetween the first and second UEs as either the first or second UE movesfrom within to outside the RLAN service region by resuming use of theGPRS connection with the Internet for transporting user data.

In another method, a wireless connection is established between firstand second UEs within the RLAN service region for conducting acommunication of user data. AAA functions for the communication betweenthe first and second UEs are conducted using the Core Network. Thewireless communication between the first and second UEs is continued aseither the first or second UE moves from within to outside the RLANservice region by using the GPRS connection with the Internet fortransporting user data of the continued communication.

A further method of mobility management is provided where the associatedCN supports AAA functions of home UEs and the GPRS connection of the RANIP Gateway is configured to tunnel AAA function information through theInternet to the Core Network. A wireless connection is establishedbetween a home UE and a second UE for conducting a communication of userdata. AAA functions for the communication are conducted using the CoreNetwork by using the GPRS connection with the Internet to tunnel AAAfunction information through the Internet to the Core Network.

This method may be used where the wireless connection is establishedwhen either the home UE or the second UE is within or outside the RLANservice region. Where one is within and the other is outside of the RLANservice region, the GPRS connection with the Internet is used fortransporting user data of the communication between the home and secondUEs.

This method may further include continuing the wireless communicationbetween the home and second UEs as one moves such that both are outsideor both are within the RLAN service region, where the use of saidGeneral Packet Radio Service (GPRS) connection with the Internet fortransporting user data is discontinued. The method may further includecontinuing the wireless communication between the home and second UEs aseither the home or second UE moves so that one is within and the otheris outside the RLAN service region by using the GPRS connection with theInternet for transporting user data for the continued communication.

In one aspect of the invention, the RLAN has as control means one ormore U-Plane and C-Plane Servers coupled with base stations. The U-PlaneServer(s) are configured to control user data flow of base stationcommunications. The C-Plane Server(s) are configured to controlsignaling for base stations communication. Preferably, the RAN IPGateway has a SGSN that is coupled with the U-plane Servers and at leastone C-Plane Server. Preferably, the U-Plane Servers and C-Plane Serversare coupled with each other, the base stations, and the RAN IP Gatewayusing stacked, layered protocol connections having a lower transportlayer configured to use Internet Protocol (IP).

Optionally, a Voice Gateway having a Pulse Code Modulation (PCM) portfor external connection may be provided for the RLAN. The Voice Gatewayis preferably coupled with a U-plane and a C-Plane Server (or an RNCwhere RNCs are used) using stacked, layered protocol connections havinga lower transport layer configured to use Internet Protocol (IP).

In another aspect of the invention, the RLAN has one or more RadioNetwork Controllers (RNCs) coupled with base stations and a RAN IPGateway to which at least one RNC is coupled via an Iu-PS interfaceusing a stacked, layered protocol connection having a lower transportlayer configured to use Internet Protocol (IP). Preferably, the RNCs arecoupled the base stations and each other using stacked, layered protocolconnections having a lower transport layer configured to use InternetProtocol (IP). Preferably, each base station has a transceiverconfigured with a Uu interface for conducting time division duplex (TDD)wideband code division multiple access (W-CDMA) wireless communicationswith UEs in a selected geographic region and the RAN IP Gateway has aSGSN that is coupled with the RNCs.

In another aspect of the invention, the RLAN supports voicecommunications over IP and has a RAN IP Gateway having a GGSN forconnection with the Internet that passes compressed voice data. The RLANis preferably connected to the Internet via an internet service provider(ISP) that has a voice gateway that converts compressed voice data andPulse Code Modulation (PCM) signaling using a known compressionprotocol, which may or may not be the type of voice compression dataused by UEs conducting wireless communications with the RLAN.

Where the UEs use one compression protocol and the RLAN is connectedwith the Internet via an ISP having a voice gateway that convertscompressed voice data and PCM signaling using a different compressionprotocol, the RLAN includes a voice data converter for convertingbetween compressed voice data of the two different compressionprotocols. Preferably, the RAN IP Gateway includes the voice dataconverter which is, for example, configured to covert between AMRcompressed voice data and G.729 compressed voice data. The RLAN may beconfigured with U-Plane and C-Plane Servers or RNCs, but preferably allcomponent interfaces within the RLAN use stacked, layered protocolconnections having a lower transport layer configured to use InternetProtocol (IP).

The invention further provides a telecommunication network having one ormore radio network for providing concurrent wireless telecommunicationservices for a plurality of UEs and an associated CN for supporting AAAfunctions of UEs for which the telecommunication network is a HomeNetwork. One or more of the radio networks is a RLAN having a RAN IPGateway that has a GGSN configured with a GI interface for connectionwith the Internet and is configured to communicate AAA functioninformation to the CN. Preferably, the RLANs each have one or more basestations that have a transceiver for conducting TDD-CDMA wirelesscommunications with UEs in a selected geographic region. Preferably, theRLANs have controllers coupled with the base stations. Preferably, theRLANs' RAN IP Gateways have a SGSN that is coupled with the respectivecontrollers.

The RLAN may be configured without a direct CN connection where the RANIP Gateway is configured for communication of AAA function informationwith the CN by tunneling data through an Internet connection.Alternatively, the RAN IP Gateway has a coupling with the CN forcommunication of AAA function information with the CN via a limitedconnection, such as a Radius/Diameter or MAP supporting connection or aconventional Iu-CS interface, or a full conventional Iu interface.

Preferably, the RAN IP Gateways have GGSNs configured for connectionwith the Internet via a GI interface. For mobile support, the GIinterface is preferably configured with Mobile IP v4 or Mobile IP v6.

Other objects and advantages of the present invention will be apparentto those skilled in the art from the following detailed description andthe drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphic illustration of a conventional UMTS network inaccordance with current 3GPP specification.

FIG. 2 is a block diagram showing various components and interfaces ofthe network illustrated in FIG. 1.

FIG. 3 is a schematic diagram of the conventional network illustrated inFIGS. 1 and 2 indicating layered stacked protocols of the variouscomponent interfaces in both signaling and user data planes.

FIG. 4 is a graphic illustration of a UMTS network including a RLAN witha direct Internet link in accordance with the teachings of the presentinvention.

FIG. 5 is a block diagram showing various components of the networkshown in FIG. 4.

FIG. 6 is a block diagram showing a variation of the network where theRLAN has no direct connection with the UMTS Core Network.

FIG. 7 is a schematic illustration of signaling data flow in the UMTSnetwork illustrated in FIG. 6.

FIG. 8 is a graphic illustration of a second variation of the UMTSnetwork illustrated in FIG. 4 wherein the RLAN has a first type oflimited connection with the UMTS Core Network.

FIG. 9 is a graphic illustration of a second variation of the UMTSnetwork illustrated in FIG. 4 wherein the RLAN has a second type oflimited connection with the UMTS Core Network.

FIGS. 10A and 10B illustrate two variations of IP packet data flow forthe networks shown in FIGS. 4, 8 and 9 wherein Mobile IP v4 protocol isimplemented by the RLAN.

FIGS. 11A and 11B illustrate two variations of IP packet data flow forthe networks shown in FIGS. 4, 8 and 9 wherein Mobile IP v6 protocol isimplemented by the RLAN.

FIG. 12 is a schematic illustration of preferred signaling plane anduser plane interfaces within a RLAN made in accordance with theteachings of the present invention.

FIG. 13 is a schematic illustration of a RLAN having a single RadioNetwork Controller in accordance with the teachings of the presentinvention.

FIG. 14 is a schematic illustration of a RLAN having multiple RadioNetwork Controllers made in accordance with the teachings of the presentinvention.

FIG. 15 is an illustrated diagram of an alternate configuration of anRLAN having separate servers for user data and control signals and alsoan optional voice gateway made in accordance with the teachings of thepresent invention.

FIG. 16 is a block diagram of components of the RLAN illustrated in FIG.15.

FIG. 17 is a schematic diagram illustrating a preferred protocol stackfor the control plane interfaces of a RLAN made in accordance with theteachings of the present invention.

FIG. 18 is a schematic diagram illustrating a preferred protocol stackfor the user plane interfaces of a RLAN made in accordance with theteachings of the present invention.

FIGS. 19, 20 and 21 are schematic diagrams illustrating three variationsof interface protocol stacks in the user plane for supporting voicecommunication between a UE having a wireless connection with an RLAN andan ISP connected to the RLAN which has a voice gateway.

FIG. 22 is a schematic diagram illustrating a variation of interfaceprotocol stacks in the control plane for supporting voice communicationbetween a UE having a wireless connection with an RLAN and an ISPconnected to the RLAN which has a voice gateway.

TABLE OF ACRONYMS 2G Second Generation 2.5G Second Generation Revision3GPP Third Generation Partnership Project AAA functions Authentication,Authorization and Accounting functions AAL2 ATM Adaptation Layer Type 2AAL5 ATM Adaptation Layer Type 5 AMR A type of voice data compressionATM Asynchronous Transfer Mode CDMA Code Division Multiple Access CNCore Network CODECs Coder/Decoders C-RNSs Control Radio NetworkSubsystems CS Circuit Switched ETSI European Telecommunications StandardInstitute ETSI SMG ETSI - Special Mobile Group FA Forwarding Address FNForeign Network G.729 A type of voice data compression GGSN Gateway GPRSSupport Node GMM GPRS Mobility Management GMSC Gateway Mobile SwitchingCenter GPRS General Packet Radio Service GSM Global System for MobileTelecommunications GTP GPRS Tunneling Protocol GW Gateway H.323/SIPH.323 Format for a Session Initiated Protocol HLR Home Location RegisterHN Home Network HSS Home Service Server IP Internet Protocol ISDNIntegrated Services Digital Network ISP Internet Service Provider Iu-CSIu sub Interface for Circuit Switched service Iu-PS Iu sub Interface forPacket Switched service IWU Inter Working Unit M3UA Message TransferPart Level 3 SCCP SS7 Adaptation Layer MAC Medium Access Control MAPMobile Application Part MSC Mobile Switching Centre NRT Non-Real TimePCM Pulse Code Modulation PLMN Public Land Mobile Network PS PacketSwitched PSTN Public Switch Telephone Network RANAP Radio Access NetworkApplication Part RAN IP Radio Access Network Internet Protocol RIP GWRAN IP Gateway RLAN Radio Local Area Network RLC Radio Link Control RNCRadio Network Controller RRC Radio Resource Control RT Real TimeSCCP/MTP Signaling Connection Control Part, Message Transfer Part SGSNServing GPRS Support Node SCTP Stream Control Transmission Protocol SMSession Management SMS Short Message Service S-RNS Serving Radio NetworkSubsystems SS7 Signaling System 7 SSCF Service Specific CoordinationFunction SSCOP Service Specific Connection Oriented Protocol TDD TimeDivision Duplex UDP/IP User Data Protocol for the Internet Protocol UEUser Equipment UMTS Universal Mobile Telecommunications System UTRANUMTS Terrestrial Radio Access Network VLR Visitor Location Register

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 4, there is shown a modified Universal MobileTerrestrial System (UMTS) network having a Radio Local Area Network(RLAN) with a direct Internet connection. As shown in FIG. 5, the RLANemploys base stations to communicate via a wireless radio interface withthe various types of User Equipments (UEs). Preferably the base stationsare of the type specified in 3GPP as node Bs. A radio controller iscoupled to the base stations to control the wireless interface.Preferably the radio controller is a Radio Network Controller (RNC) madein accordance with 3GPP specification. Various combinations of Node Bsand RNCs may be employed as used in a conventional 3GPP UTRAN.Collectively, the geographic ranges of the wireless communicationsconducted with the base stations of the RLAN defines the RLAN's servicecoverage area.

Unlike a conventional UTRAN, the RLAN of the present invention includesa Radio Access Network Internet Protocol (RAN IP) gateway which providesconnectivity for the RLAN outside its service coverage area, i.e. thegeographic area served by the wireless communication with its basestations. As illustrated in FIGS. 4 and 5, the RAN IP gateway has adirect Internet connection and may have the standard direct UMTS networkconnection through an Iu interface with an associated Core Network.Alternatively, as illustrated in FIG. 6, the direct interface between anassociated Core Network and the RAN IP gateway may be omitted so thatthe RAN IP Gateway can have only a direct connection with the Internet.In such case, as illustrated in FIG. 7, the RLAN of the presentinvention may still form a part of a UMTS by the tunneling of controland AAA function information to a Core Network which serves as its HomeCN.

FIGS. 8 and 9 illustrate two separate versions of an RLAN made inaccordance with the teachings of the present invention wherein the RANIP Gateway is configured with a control signal port for establishing alimited direct connection with its Home UMTS Core Network. Inparticular, the limited connectivity transports information needed toprovide AAA function support for the CN.

The RAN IP Gateway control signal port may be configured, as illustratedin FIG. 8, to provide control signal data using radius/diameter basedaccess in which case the core network includes an Inter Working Unit(IWU) as specified in 3GPP which converts AAA function information intoconventional Mobile Application Part (MAP) signaling for connection withthe HSS/HLR of the Core Network. Alternatively, as illustrated in FIG.9, the RAN IP Gateway control signal port can be configured as a subsetof a standard Gr interface which supports MAP signaling which can bedirectly used by the HSS/HLR of the CN.

Preferably, the RAN IP Gateway employs a standard GI interface with theInternet and can be utilized as a stand-alone system without anyassociation with a Core Network of a UMTS. However, in order to supportmobility management with roaming and hand-over services available forsubscriber UEs of the RLAN, an AAA function connection with a CoreNetwork, such as by way of the various alternatives illustrated in FIGS.7, 8 and 9, is desirable. In such case, in addition to a standard GIinterface between the RAN IP Gateway of the RLAN and the Internet, amobile IP protocol is supported. Preferred examples of such mobile IPprotocols are the Mobile IP v4 protocol and the Mobile IP v6 protocol asspecified by IETF.

FIG. 10 illustrates IP packet data flow for a communication between afirst UE having a wireless connection with the RLAN and a second UEoutside the wireless service region of the RLAN where Mobile IP v4 isimplemented on the GI interface between the RAN IP Gateway and theInternet. In such case, user data from the first UE is sent in IP packetformat from the RAN IP Gateway of the RLAN through the Internet to theaddress provided by the second UE. The second UE communications aredirected to the Home Address of the first UE which is maintained at theCore Network since in this example the first UE has the CN as its HomeCN. The CN receives the IP data packets from the second UE and then theCN forwards the IP packets to the current location of the first UE whichis maintained in the CN's HLR as the Forwarding Address (FA) of thefirst UE.

In this example, since the first UE is “home”, the CN tunnels the IPPackets through the Internet to the RAN IP gateway for communication tothe first UE. In the case of the first UE traveling outside of the RLAN,its location will be registered with the Core Network and the datapackets directed to the address where the first UE is currently locatedbe used by the core network to direct the IP packet data to the currentlocation of the first UE.

FIG. 10B illustrates an alternate approach where Mobile IP v4 isimplemented on the GI interface using with reverse path tunneling suchthat the RLAN directs the IP packets of the first UE's user data to theHome CN where they are relayed to the second UE in a conventionalmanner.

When the RLAN has connectivity using a GI interface that implementsMobile IP v6, the IP packet data exchange between the first UE and thesecond UE will contain binding updates, as illustrated in FIG. 11A,which will reflect any redirection of the IP packets needed forhand-over. FIG. 11B illustrates an alternative approach using a GIinterface implementing mobile IP v6 that includes tunneling between theRLAN and the Home CN. In such case, the CN directly tracks locationinformation of the first UE and the second UE may communicate with thefirst UE's Home CN in any type of conventional manner.

With reference to FIG. 12, there is shown the construction of preferredinterfaces between the components of the RLAN of the present invention.The UE interface between the RLAN via the base station, Node B, ispreferably a standard Uu interface for connection with UEs as specifiedby 3GPP. An Iub interface between each Node B and RNC is preferablyimplemented both in the control plane and the user data plane as alayered stacked protocol having Internet Protocol (IP) as the transportlayer. Similarly at least a subset of an Iu-PS interface is preferablyprovided between an RNC and the RAN IP Gateway that is a layered stackedprotocol having IP as the transport layer.

In a conventional UMTS where SS7 is implemented over ATM, theMTP3/SSCF/SSCOP layers help SCCP, which is the top layer of the SS7stack, to plug onto an underlying ATM stack. In the preferred IPapproach used in conjunction with the present invention, the M3UA/SCTPstack helps SCCP connect onto IP. Essentially, the M3UA/SCTP stack inthe preferred IP-based configuration replaces the MTP3/SSCF/SSCOP layersthat are used in the conventional SS7-over-ATM approach. The specificdetails of these standard protocol stack architecture are defined in theIETF (Internet) standards. The use of IP in lieu of ATS enablescost-savings as well as PICO cells for office and campus departments.

Where the RLAN has multiple RNCs, the RNCs can be interfaced via an Iurinterface having layered stacked protocols for both the signaling planeand user plane using an IP transport layer. Each RNC is connected to oneor more Node Bs which in turn serve in plurality of UEs withinrespective geographic areas that may overlap to enable intra-RLANservice region handover.

Handover of a UE communication with one Node B within the RLAN toanother Node B within the RLAN, intra-RLAN handover, is conducted in theconventional manner specified in 3GPP for intra-UTRAN handover. However,when a UE communicating with a Node B of the RLAN moves outside the RLANservice region, handover is implemented via the RAN IP gateway utilizingIP packet service, preferably, implemented with Mobile IP v4 or MobileIP v6 as discussed above.

FIG. 13 illustrates the subcomponents of a preferred RLAN in accordancewith the present invention. The RNC can be divided into standard Controland Serving Radio Network Subsystems (C-RNSs and S-RNSs) connected by aninternal Iur interface. In such a configuration, the S-RNS functions arecoupled to a SGSN subcomponent of the RAN IP gateway which supports asubset of the standard SGSN functions, namely, GPRS Mobility Management(GMM), Session Management (SM) and Short Message Service (SMS). The SGSNsubcomponent interfaces with a GGSN subcomponent having a subset of astandard GGSN functions including an access router and gateway functionssupport for the SGNS subcomponent functions and a GI interface withmobile IP for external connectivity to the Internet. The SGSNsubcomponent interface with the GGSN subcomponent is preferably viamodified Gn/Gp interface, being a subset of the standard Gn/Gp interfacefor a CN's SGNS and GGSN.

Optionally, the RAN IP Gateway has an AAA function communicationsubcomponent that is also connected to the SGSN subcomponent andprovides a port for limited external connectivity to an associated CN.The port supporting either a Gr interface or a Radius/Diameter interfaceas discussed above in connection with FIGS. 8 and 9.

Multiple RNCs of the RLAN can be provided coupled with the SGSNsubcomponent by an Iu-PS interface which includes sufficientconnectivity to support the functions of the SGSN subcomponent. Wheremultiple RNCs are provided, they are preferably coupled by a standardIur interface which utilizes an IP transport layer.

The use of IP for the transport layer of the various components of theRLAN readily lends itself to implementing the RNC functions in separatecomputer servers to independently process the user data ofcommunications and the signaling as illustrated in FIG. 15. Referring toFIG. 16, there is a component diagram where the radio control means isdivided between U-plane and C-plane servers. In addition to the basicRLAN components, an optional Voice Gateway is also illustrated in FIGS.15 and 16.

Each Node B of the RLAN has a connection using an IP transport layerwith a U-plane server which transports user data. Each Node B of theRLAN also has a separate connection with a C-plane server via a standardIub signal control interface having an IP transport layer. Both theU-plane server and C-plane server are connected to the IP gateway usinglayered stacked protocols, preferably having IP as the transport layer.

For multiple C-plane server configurations, each can be coupled to eachother via a standard Iur interface, but only one is required to bedirectly connected to the RIP GW. This allows the sharing of resourcesfor control signal processing which is useful when one area of the RLANbecomes much busier in other areas to spread out the signal processingbetween C-plane servers. A plurality of C-plane and U-plane servers canbe connected in a mesh network for sharing both C-plane and U-planeresources via stacked layer protocols preferably having an IP transportlayer.

Where the optional voice gateway having external connectivity via PCMcircuit is provided, the U-plane server and C-plane server are coupledto the voice gateway via a stacked layer protocols preferably having anIP transport layer. The C-plane server is then coupled to the U-planeserver via a Media gateway control protocol gateway (Megaco) over an IPtransport layer. Megaco is a control plane protocol that sets up thebearer connection(s) between a Voice gateway elements, as part of callestablishment.

Referring to FIGS. 17 and 18, there are shown, respectively, preferredC-plane and U-plane protocol stacks which are implemented between theNode Bs, RNCs (or U- and C-plane servers) and the RAN IP Gateway of theRLAN. In each drawing, the preferred over air protocol stack implementedvia the Uu interface with UEs is also shown.

The RLAN can be configured with voice support over its external IPconnection. In such case, the RIP gateway is connected with an InternetService Provider (ISP) which in turn has a PCM voice gateway. The PCMvoice gateway converts voice compression data into a Pulse CodeModulation (PCM) format for external voice communications.

Vocoders are provided that use Coder/Decoders (CODECs) for compressionof voice data. Two common types vocoder formats are the AMR vocoderformat and G.729 compression format. FIGS. 19 and 21 show preferredU-plane protocol stacks which are implemented where the voice gateway ofthe ISP to which the RLAN is connected uses the same type of voicecompression interface as the UE. AMR vocoder format being illustrated inFIG. 19; G.729 vocoder format being illustrated in FIG. 21. The voiceover IP is simply transferred as regular packet data over the IPinterface without change.

Where the UE utilizes a different voice compression protocol than thevoice gateway of the ISP, a converter is provided in the RNC or the RANIP Gateway. FIG. 20 shows preferred U-plane protocol stacks, where theUE utilizes an AMR vocoder and the ISP voice gateway utilizes a G.729vocoder. Preferably, the RAN IP Gateway (RIP GW) includes the AMR/G.729converter. In the case illustrated in FIG. 20, the converter convertsAMR compressed data received from the node B to G.729 format compressedvoice format for output by the RIP GW. Where the RLAN utilizes separateU-plane and C-plane servers, the compressed voice data is transported bya U-plane server and the converters may be located in either the U-planeservers or the IP gateway.

With reference from FIGS. 22, there is shown preferred control planeprotocol stack architecture for supporting voice using standard 11.323format for a Session Initiated Protocol (11.323/SIP) over TCP/UDP carryby IP. The control signaling is essentially the same irrespective of thetype of voice data compression conducted in the U-Place.

Although the present invention has been described based on particularconfigurations, other variations will be apparent to those of ordinaryskill in the art and are within the scope of the present invention.

What is claimed is:
 1. A user equipment comprising: a receiver, atransmitter, and a processor, wherein the receiver, the transmitter, andthe processor are configured to cause the user equipment: to communicatecircuit switched voice data with a first cellular radio access network(RAN); and to communicate voice over Internet protocol (VoIP) packetsusing session initiation protocol (SIP) with a second cellular RAN,wherein the second cellular RAN does not support circuit switched voicecommunication.
 2. The user equipment of claim 1 wherein the secondcellular radio access network is IP based.
 3. The user equipment ofclaim 1 wherein the receiver, the transmitter, and the processor areconfigured to cause the user equipment to use an AMR type codec toproduce voice data and to process the produced voice data to produce theVoIP packets.
 4. The user equipment of claim 1 wherein the receiver, thetransmitter, and the processor are configured to cause the userequipment to process VoIP packets and to use an AMR type codec torecover a voice signal.
 5. The user equipment of claim 1 wherein thereceiver, the transmitter, and the processor are configured to cause theuser equipment to send the VoIP packets to an IP gateway associated withthe second radio access network.
 6. A method comprising: communicating,by a user equipment, circuit switched voice data with a first cellularradio access network (RAN); and communicating, by the user equipment,voice over Internet protocol (VoIP) packets using session initiationprotocol (SIP) with a second cellular RAN, wherein the second cellularRAN does not support circuit switched voice communication.
 7. The methodof claim 6 wherein the second cellular RAN is IP based.
 8. The method ofclaim 6 comprising using an AMR type codec to produce voice data andprocessing the produced voice data to produce the VoIP packets.
 9. Themethod of claim 6 comprising processing VoIP packets and using an AMRtype codec to recover a voice signal.
 10. The method of claim 6 whereincomprising sending, by the user equipment, the VoIP packets to an IPgateway associated with the second radio access network.